RESUMO
A ring trial among five European laboratories was organized to reach consistency in microsatellite (MS) typing of the zoonotic parasite Toxoplasma gondii. Three sample sets were circulated and analyzed by each laboratory following a previously published method that is based on fragment length polymorphism of 15 MS markers. The first sample set compared typing results in general and focused on effects of DNA concentration; the second sample set focused on the polymorphic fingerprinting markers that can differentiate T. gondii strains within the same archetypal lineage; and the third set focused on non-archetypal genotypes. Methodological variations between laboratories, including the software programs used to determine MS fragment length, were collated using a questionnaire. Overall, lineage-level typing results reached a high level of agreement, especially in samples with the highest DNA concentrations. However, laboratory-specific differences were observed for particular markers. Major median differences in fragment length, of up to 6 base pairs, were related to the fluorophore used to label fragment-specific primers. In addition, primer pairs with identical sequences obtained from different suppliers resulted in fragments of differing length. Furthermore, differences in the way the sequencing profiles were assessed and interpreted may have led to deviating results in fragment length determination. Harmonization of MS typing, for example, by using the same fluorophores or by numerical adjustments applied to the fragment-lengths determined, could improve the uniformity of the results across laboratories. This is the first interlaboratory comparison, providing guidelines (added as a supplement) for the optimization of this technique.
Assuntos
Toxoplasma , Toxoplasmose Animal , Humanos , Animais , Toxoplasma/genética , Variação Genética , Polimorfismo de Fragmento de Restrição , DNA de Protozoário/genética , Repetições de Microssatélites , GenótipoRESUMO
BACKGROUND: Bacillus cereus is a ubiquitous telluric organism. B. cereus endocarditis is a rare condition seen mostly in prosthetic heart valves and among intravenous drug users. We report a new case of a patient without risk factors and with a good clinical outcome not requiring valve replacement. CASE REPORT: In October 2014, a 50-year-old woman was referred to the dermatology department of Lille University Hospital for lower-limb wounds developing 6 months earlier. She presented fever without clinical signs of infection, except for the lower-limbs wounds. Blood cultures revealed the presence of B. cereus. Transesophageal echocardiography was performed and revealed two foci of aortic valve vegetation with a diameter of 5mm. After bacterial sensitivity testing, rifampicin and levofloxacin treatment was given for six weeks, with complete remission. A skin graft was performed and good improvement was seen. DISCUSSION: Nineteen cases of B. cereus endocarditis have been described previously, only one of which was without risk factors. We described a case of complete remission after a 6-week course of antibiotics. Our case demonstrates that BC should not be considered as a blood culture contamination, and that treatment may be complex due to antibiotic resistance.
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Antibacterianos/uso terapêutico , Bacillus cereus/isolamento & purificação , Endocardite/tratamento farmacológico , Endocardite/microbiologia , Úlcera da Perna/complicações , Levofloxacino/uso terapêutico , Rifampina/uso terapêutico , Quimioterapia Combinada , Endocardite/diagnóstico , Feminino , Humanos , Úlcera da Perna/microbiologia , Úlcera da Perna/terapia , Pessoa de Meia-Idade , Fatores de Risco , Fatores de Tempo , Resultado do TratamentoRESUMO
In the last decade, we faced a large number of emerging pathogens. As a consequence we had to adapt our medical practice as well as our health system. This review summarizes the main features of the recent emerging pathogens with a particular focus on the recent and ongoing Ebola outbreak, we tried to evaluate the consequences on our national health management.
RESUMO
The previous article in this series described the physico-chemical properties and chemical compositions of the two phases of the limonene-ethyl acetate-ethanol-water biphasic liquid system. This system was designed to be a "green" version of the so-called Arizona (AZ) scale of heptane-ethyl acetate-methanol compositions in which the heptane-ethyl acetate volume ratio is exactly the same as the methanol-water ratio. The first major difference between the standard and "green" AZ systems is the difference in upper and lower phase densities. The higher density of limonene compared with heptane greatly reduces the density difference of the "green" system: half the compositions have a density difference lower than 0.06 g mL(-1), precluding their use in hydrodynamic CCC columns. The other major difference is the phase polarity. The better distribution of ethanol between the upper organic and lower aqueous phases of the "green" AZ scale renders them more polar than their counterparts in standard heptane-based compositions. The test solutes aspirin and coumarin have higher distribution constants in the "green" AZ compositions. It is revealed that a hydrostatic column is suitable for use with all "green" compositions, with very good phase retention and limited driving pressure at high flow rates. A hydrodynamic column only functioned at limited flow rates with polar compositions of sufficient phase-density difference. The CCC chromatograms obtained with different compositions and columns are shown, and their peak position and sharpness discussed.
RESUMO
We report the first case of cerebral abscess due to a novel species of Nocardia in a heart transplant patient and describe the antimicrobial susceptibility of this isolate. As our patient was intolerant to trimethoprim-sulfamethoxazole, we also discuss alternative therapeutic options in brain abscess due to Nocardia sp.
Assuntos
Abscesso Encefálico/microbiologia , Hospedeiro Imunocomprometido , Nocardiose/microbiologia , Nocardia/classificação , Nocardia/genética , Adulto , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Abscesso Encefálico/diagnóstico , Abscesso Encefálico/tratamento farmacológico , Feminino , Genes Bacterianos , Transplante de Coração/efeitos adversos , Humanos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Nocardia/efeitos dos fármacos , Nocardiose/diagnóstico , Nocardiose/tratamento farmacológico , FilogeniaRESUMO
The efficient immobilization of antibodies on monolithic support is one of the most critical steps when preparing immunoaffinity supports. In this work, the ADECA (amino density estimation by colorimetric assay) method was adapted to tridimensional supports (in a dynamic mode) and proved to be efficient to characterize the antibodies grafting efficiency on 15.3±0.9mg porous glycidyl methacrylate (GMA)-co-ethylene dimethacrylate (EDMA) monolithic columns. The amount of grafted antibodies measured in situ on the monolith by ADECA (8.2±0.2µg of antibodies per milligram of monolith) was consistent with values obtained by bicinchoninic acid assay (BCA) after crushing the monolith. ADECA was shown to be less time-consuming and more versatile than BCA. The ADECA method was further implemented to thoroughly study and optimize the antibody grafting conditions (influence of pH and kinetics of the grafting step) on GMA-based monoliths and to check the covalent nature of the antibody/surface linking and its stability. Using the total amount of grafted antibodies and the amount of recognized antigen, we found that 65±6% of antibodies were able to capture their antigen. Finally, the grafting of Fab and F(ab')(2) fragments demonstrated that no significant improvement of the global binding capacity of the monolith was obtained.
Assuntos
Anticorpos Imobilizados/química , Cromatografia de Afinidade/métodos , Metilmetacrilatos/química , Adsorção , Anticorpos Imobilizados/imunologia , Colorimetria , Imunoensaio , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/imunologia , Cinética , Porosidade , Quinolinas/química , Reprodutibilidade dos Testes , Corantes de Rosanilina/química , Fatores de TempoRESUMO
Blood cultures from outpatients receiving home parenteral nutrition (HPN) via long-term central venous access (CVA) were retrospectively analyzed from January 2003 to May 2009. When infection of the CVA was not due to Staphylococcus aureus, Pseudomonas aeruginosa, or Candida, catheter salvage was attempted for a maximum of three consecutive infections on the same CVA. Factors influencing the time-to-next-infection were studied, whether the catheter was changed after the last infection or not. Neither the McCabe score, age, history of cancer, diabetes mellitus nor immunosuppression, curative antibiotic lock, type of bacteria, type or duration of treatment had an influence on the time-to-next-infection. The time-to-next-infection was significantly associated with the status of CVA (saved or changed) and its type (tunneled catheter with or without a cuff, or implanted port catheter).
Assuntos
Infecções Relacionadas a Cateter/epidemiologia , Nutrição Parenteral no Domicílio/efeitos adversos , Sepse/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Infecções Relacionadas a Cateter/microbiologia , Humanos , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos , Fatores de Risco , Sepse/microbiologia , Fatores de TempoRESUMO
Many countries with a high perinatal level have started a policy of vaccination of pregnant women against pertussis. To date, France has not chosen this policy. The objective was to review knowledge on pertussis mortality in infants. Compare the strategies available to protect the infant before his first vaccination, scheduled for two months of age. We proceeded to a litterature analysis, from January 1998 to 2021. Search by the following keywords used ; "Whooping cough, vaccination, pregnancy, strategy, cocooning", on the scientific basis of "Pubmed", as well as French and foreign vaccination recommendations. Currently 90% of whooping cough deaths are concerning infants under six months of age and this mortality represents 2% of mortality in the first year of life. Vaccination at birth is not effective. The cocooning strategy, which consists of vaccinating those around the child, is expensive and difficult to implement. A systematic vaccination policy for pregnant women is effective and reasonably expensive when compared to the cocooning strategy. In England, it was recently accompanied by a 78% reduction in confirmed cases of pertussis in infants under six months of age. In conclusion, compared to cocooning strategy, pertussis vaccination of pregnant women appears more effective and cost-effective, and this with each pregnancy.
Assuntos
Coqueluche , Criança , Análise Custo-Benefício , Feminino , Humanos , Lactente , Recém-Nascido , Parto , Gravidez , Gestantes , Vacinação , Coqueluche/prevenção & controleRESUMO
OBJECTIVES: To assess the quality of prescription of fluoroquinolons, aminosids and amoxicillin-clavulanic acids in medicine departments. METHODS: Data on target antibiotic prescription were collected on a given day and confronted to local recommendations and literature guidelines. Evaluation of antibiotic therapy was done by assessing molecule choice, administration conditions (dosages, route and administration schedule, treatment duration), reassessment of treatments 48-72 h later, dose adaptation of aminosids depending on serum monitoring. RESULTS: Sixty-three patients were included and 67 "target" antibiotics were prescribed. Prevalence of antibiotic-treated patients was 24.4%, and 14.6% for "target" antibiotic-treated patients. Antibiotic choice was appropriate in 67% of prescriptions. Dosages were adequates in 94% of case and administration schedule in 97% of cases. The oral route administration as soon as possible was applied to half of patients. Treatment duration were respected for 94% of prescriptions. Reassessment of antibiotic therapy 48-72 h later was realized in 66% of cases. Dose adaptation of aminosids, when necessary, was realized on one third of cases. For all the quality criteria assessed, the overall frequency of prescription conformity was 44%. CONCLUSION: Large diffusion of protocols, systematic reassessment of treatments at 48-72 h, promotion of training sessions for new prescribers in the institution, reinforcing the function of medical correspondents in antibiotic therapy and infectiologists, periodic evaluation of antibiotic therapy, should improve the quality of antibiotic therapy.
Assuntos
Aminoglicosídeos/uso terapêutico , Combinação Amoxicilina e Clavulanato de Potássio/uso terapêutico , Antibacterianos/uso terapêutico , Prescrições de Medicamentos/estatística & dados numéricos , Fluoroquinolonas/uso terapêutico , Fidelidade a Diretrizes/estatística & dados numéricos , Hospitais de Ensino/estatística & dados numéricos , Idoso , Aminoglicosídeos/administração & dosagem , Combinação Amoxicilina e Clavulanato de Potássio/administração & dosagem , Antibacterianos/administração & dosagem , Infecções Bacterianas/tratamento farmacológico , Prescrições de Medicamentos/normas , Feminino , Fluoroquinolonas/administração & dosagem , França , Departamentos Hospitalares/estatística & dados numéricos , Registros Hospitalares/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como AssuntoRESUMO
BACKGROUND: Borderline personality disorder (BPD) accounts for 10% of outpatient psychiatric practice. The risk of suicide attempts is high and the psychosocial impairment significant. Different theoretical streams have suggested psychotherapeutical approaches for BPD. OBJECTIVE: to examine the efficacy of psychotherapy for BPD patients on affective symptoms, behavioural outcomes, interpersonal and social functioning, as well as BPD criteria. METHODS: We reviewed the medical literature from 1990 to 2008 on Medline by combining the following keywords "borderline personality disorder" and "psychotherapy" (inclusion criteria). We restricted the analysis to "randomised control trial" or "meta analysis". RESULTS: Of the 39 abstracts that came out from the search, we selected 17 (44%) after applying the exclusion criteria. According to our review, different types of psychotherapies have shown some efficacy on reducing affective symptoms and BPD criteria, as well as improving behavioural outcomes and psychosocial functioning. Dialectical behavioural therapy presents the best-documented efficacy, notably on reducing self-mutilating and suicidal behaviours (five randomized controlled trials [RCT]). Mentalization based treatment seems to be efficient on the four types of outcomes, but has been the object of only one RCT. Finally, some evidence suggests that Manual Assisted Cognitive Treatment and Systems Training for Emotional Predictability and Problem Solving are the most cost-effective and easiest to be implemented. CONCLUSION: According to our review, some evidence supports an efficiency of psychotherapies in the management of several features of BPD. It is likely that, depending on the target symptoms, one type of therapy might be more efficient than another. The acceptability of these long-term treatments is however unknown.
Assuntos
Transtorno da Personalidade Borderline/terapia , Psicoterapia/métodos , Afeto , Transtorno da Personalidade Borderline/diagnóstico , Transtorno da Personalidade Borderline/psicologia , Humanos , Relações Interpessoais , Assistência de Longa Duração , Avaliação de Processos e Resultados em Cuidados de Saúde , Ensaios Clínicos Controlados Aleatórios como Assunto , Automutilação/prevenção & controle , Automutilação/psicologia , Ajustamento Social , Comportamento Social , Tentativa de Suicídio/prevenção & controle , Tentativa de Suicídio/psicologiaRESUMO
Colonization resistance by gut microbiota is a fundamental phenomenon in infection prevention and control. Hospitalized patients may be exposed to multi-drug-resistant bacteria when hand hygiene compliance among healthcare workers is not adequate. An additional layer of defence is provided by the healthy gut microbiota, which helps clear the exogenous bacteria and acts as a safety net when hand hygiene procedures are not followed. This narrative review focuses on the role of the gut microbiota in colonization resistance against multi-drug-resistant bacteria, and its implications for infection control. The review discusses the underlying mechanisms of colonization resistance (direct or indirect), the concept of resilience of the gut microbiota, the link between the antimicrobial spectrum and gut dysbiosis, and possible therapeutic strategies. Antimicrobial stewardship is crucial to maximize the effects of colonization resistance. Avoiding unnecessary antimicrobial therapy, shortening the antimicrobial duration as much as possible, and favouring antibiotics with low anti-anaerobe activity may decrease the acquisition and expansion of multi-drug-resistant bacteria. Even after antimicrobial therapy, the resilience of the gut microbiota often occurs spontaneously. Spontaneous resilience explains the existence of a window of opportunity for colonization of multi-drug-resistant bacteria during or just after antimicrobial therapy. Strategies favouring resilience of the gut microbiota, such as high-fibre diets or precision probiotics, should be evaluated.
Assuntos
Microbioma Gastrointestinal , Preparações Farmacêuticas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana Múltipla , Disbiose , HumanosRESUMO
Chlamydia trachomatis (CT) is the most common sexually transmitted bacterial infection worldwide. It is asymptomatic in most cases and mainly affects young women, with potential long term sequelae (pelvic inflammatory disease, tubal infertility, obstetric complications). The impact on male fertility is controversial. Screening methods as well as antibiotics use have recently been reassessed due to resistance phenomena and the negative effect on the urogenital microbiota. Positive CT serology may be indicative of tuboperitoneal pathology, which may not be noticed on hysterosalpingography. New research on single-nucleotide polymorphisms (SNPs) aims to establish a patient profile at higher risk of infectious tubal damage due to CT. CT seropositivity is also associated with decreased spontaneous pregnancy rates and is a predictive factor for obstetrical complications.
Assuntos
Infecções por Chlamydia , Infertilidade Feminina , Infertilidade , Doença Inflamatória Pélvica , Infecções por Chlamydia/complicações , Infecções por Chlamydia/diagnóstico , Chlamydia trachomatis , Feminino , Humanos , Histerossalpingografia , Infertilidade Feminina/etiologia , Masculino , GravidezRESUMO
BACKGROUND: Most pregnant women who self-report penicillin allergy are not truly penicillin-allergic and this misunderstanding often leads to administration of inappropriate antibiotic therapy. Decision algorithms have been developed to guide antibiotic selection but major discrepancies have been reported between guidelines and clinical practice. We aimed to optimize the prescription of antibiotics for pregnant women who self-reported penicillin allergy, using an educational intervention about the classification of penicillin allergies that targeted gynecologists, anesthesiologists and midwives. METHODS: This quasi-experimental study assessed the effect of an educational intervention about the classification of penicillin allergy. For six months, a combination of two strategies was used, namely dissemination of printed educational materials and group education. The principal study endpoint was the appropriateness of the antibiotic therapy, defined in advance for each level of allergic risk. RESULTS: The pre-intervention phase included 903 women; one year after its conclusion, the post-intervention phase began and included 892 women. The prevalence of self-reported penicillin allergy was stable over the two periods (6.8% before vs 5.4% after, P=0.24). The clinical classification of penicillin allergies was more often used after the educational intervention (68% vs 100%, P<0.001). The appropriateness of the antibiotic therapy prescribed to self-reported penicillin allergic-women increased significantly between the two periods, from 5/29 (17.2%) to 18/27 (66.7%, P<0.001). CONCLUSION: An educational intervention about penicillin allergy classification was associated with an improvement in the choice of appropriate antibiotic therapy among women who had reported penicillin allergy.
Assuntos
Antibacterianos/efeitos adversos , Hipersensibilidade a Drogas/classificação , Educação de Pacientes como Assunto , Penicilinas/efeitos adversos , Feminino , Humanos , Gravidez , GestantesRESUMO
Transvascular transport of labeled-albumin is used to study endothelial permeability in experimental murine models of pulmonary infections. But radio-tagged albumin necessitates heavy safety procedures in terms of storage, manipulation and evacuation. The authors tested fluorescein isothiocyanate-tagged albumin (FITC-albumin) as a new marker for determination of endothelial permeability in a murine model of lung infection by Pseudomonas aeruginosa PAO1, in comparison with a standard method with (125)I-albumin. The mean permeability +/- SEM measured with (125)I-albumin was 2.45%/2 h +/- 0.37 for the control mice and 6.65%/2 h +/- 0.77 for the infected ones (P < .0001). With FITC-albumin, results obtained for both groups were respectively 4.96%/2 h +/- 0.64 and 11.5%/2 h +/- 1.2 (P < .0001). Spearman's rank coefficient was equal to .88 (P < .0001), showing a very strong correlation between both methods of measurement. The Bland-Altman analysis of bias revealed that there was no significant bias between FITC-albumin-derived and (125)I-albumin-derived values. The correction of the values obtained in plasma and lung homogenate supernatants by the subtraction of natural spontaneous fluorescence measured in these samples was crucial for the calculation of endothelial permeability in this new method. We believe that FITC-albumin can be useful for assessment of endothelial permeability in murine models of pulmonary diseases.
Assuntos
Permeabilidade Capilar , Endotélio Vascular/metabolismo , Fluoresceína-5-Isotiocianato/análogos & derivados , Albumina Sérica , Animais , Fluoresceína-5-Isotiocianato/farmacocinética , Radioisótopos do Iodo/farmacocinética , Métodos , Camundongos , Pseudomonas aeruginosa , Reprodutibilidade dos Testes , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/patologia , Albumina Sérica/farmacocinéticaRESUMO
Postpartum endometritis accounts for 2% of postpartum infections in developed countries. In France, 2.3% of deaths are attributed to puerperal infections. The most important risk factor is cesarean delivery, especially if it is done after the start of labor. Bacteria of the vaginal microbiota are associated with postpartum endometritis. Symptoms are abdomino-pelvic pain, hyperthermia and abnormal lochia. The diagnosis is confirmed by uterine mobilization pain. The first-line antibiotic therapy is amoxicillin-clavulanic acid 3 to 6 grams per day depending on the weight, intravenously or orally. In case of impossibility to use penicillins (anaphylaxis for example), the combination of clindamycin 600mg×4/d plus gentamicin 5mg/kg×1/d may be use, it must be a specialized decision in case of maternal breastfeeding. The treatment is continued until obtaining 48hours of apyrexia and the disappearance of pelvic pain. In case of persistence of fever and/or pelvic pain after 72hours of antibiotic therapy, pelvic imaging should be performed for placental retention, septic thrombophlebitis, deep abscess or any other surgical complication and eliminate differential diagnoses. It is important to highlight the difficulties of interpreting endo-uterine images in ultrasound. Hypocoagulant heparin therapy should be started in case of septic thrombophlebitis for 6 weeks, or longer if there are complications such as embolism or thrombotic risk factors. Regarding prevention, during a caesarean section, a vaginal swab with iodinated polividone or chlorhexidine is recommended before caesarean if possible, and extraction of the placenta must be spontaneous.
Assuntos
Endometrite , Doença Inflamatória Pélvica , Combinação Amoxicilina e Clavulanato de Potássio/uso terapêutico , Antibacterianos/uso terapêutico , Anticoagulantes/uso terapêutico , Cesárea/efeitos adversos , Endometrite/diagnóstico , Endometrite/tratamento farmacológico , Endometrite/microbiologia , Feminino , Febre , Humanos , Doença Inflamatória Pélvica/diagnóstico , Doença Inflamatória Pélvica/tratamento farmacológico , Doença Inflamatória Pélvica/microbiologia , Dor Pélvica , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/tratamento farmacológico , Gravidez , Infecção Puerperal , Fatores de Risco , Tromboflebite/diagnóstico , Tromboflebite/tratamento farmacológico , Vagina/microbiologiaRESUMO
OBJECTIVES: To provide up-to-date guidelines on management of pelvic inflammatory disease (PID). METHODS: An initial search of the Cochrane database, PubMed, and Embase was performed using keywords related to PID to identify reports in any language published between January 1990 and January 2012, with an update in 2018. All identified reports published in French and English relevant to the areas of focus were included. A level of evidence based on the quality of the data available was applied for each area of focus and used for the guidelines. RESULTS: PID must be suspected when spontaneous pelvic pain is associated with induced adnexal or uterine pain (grade B). Pelvic ultrasonography is necessary to exclude tubo-ovarian abscess (TOA) (grade C). Microbiological diagnosis requires endocervical and TOA sampling for molecular and bacteriological analysis (grade B). First-line treatment for uncomplicated PID combines ceftriaxone 1g, once, by intra-muscular (IM) or intra-venous (IV) route, doxycycline 100mg×2/d, and metronidazole 500mg×2/d oral (PO) for 10 days (grade A). First-line treatment for complicated PID combines IV ceftriaxone 1 to 2g/d until clinical improvement, doxycycline 100mg×2/d, IV or PO, and metronidazole 500mg×3/d, IV or PO for 14days (grade B). Drainage of TOA is indicated if the collection measures more than 3cm (grade B). Follow-up is required in women with sexually transmitted infections (STI) (grade C). The use of condoms is recommended (grade B). Vaginal sampling for microbiological diagnosis is recommended 3 to 6months after PID (grade C), before the insertion of an intra-uterine device (grade B), before elective termination of pregnancy or hysterosalpingography. Targeted antibiotics on identified bacteria are better than systematic antibioprophylaxis in those conditions. CONCLUSIONS: Current management of PID requires easily reproducible investigations and antibiotics adapted to STI and vaginal microbiota.
Assuntos
Doença Inflamatória Pélvica , Antibacterianos/administração & dosagem , Feminino , Humanos , Infecções/tratamento farmacológico , Infecções/microbiologia , Dispositivos Intrauterinos , Doença Inflamatória Pélvica/diagnóstico , Doença Inflamatória Pélvica/microbiologia , Doença Inflamatória Pélvica/terapia , Dor Pélvica , Infecções Sexualmente Transmissíveis , UltrassonografiaRESUMO
Respiratory isolates of Pseudomonas aeruginosa were collected from 58 critically-ill patients with ventilator-associated pneumonia. Expression of elastase and pyocyanin was assessed semi-quantitatively, while quorum-sensing activity was assessed by quantifying the levels of the autoinducers N-3-oxododecanoyl-L-homoserine lactone (C12-HSL) and N-butanoyl-L-homoserine lactone (C4-HSL). Correlations were sought between quorum-sensing activity and the expression of these two virulence factors, and all results were compared to those obtained with the laboratory reference strains PA103, a strain defective in quorum-sensing, and PAO1, a functional quorum-sensing strain. More than two-thirds of clinically pathogenic isolates had increased levels of elastase and/or pyocyanin, and high quorum-sensing activity, as assessed by autoinducer levels. However, a strong correlation between quorum-sensing activity and virulence factor production was revealed only for elastase and not for pyocyanin (C12-HSL/elastase, r = 0.7, p 2 x 10(-9); C4-HSL/elastase, r = 0.7, p 2 x 10(-9)). These data suggest that the pathogenicity of P. aeruginosa isolates from critically-ill patients with ventilator-associated pneumonia is caused, at least in part, by an increase in elastase production regulated by quorum-sensing, while increased pyocyanin production in these isolates may be regulated predominantly by mechanisms other than quorum-sensing.
Assuntos
Regulação Bacteriana da Expressão Gênica , Pneumonia Associada à Ventilação Mecânica/microbiologia , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/patogenicidade , Percepção de Quorum , Fatores de Virulência/metabolismo , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Proteínas de Bactérias , Humanos , Elastase Pancreática/genética , Elastase Pancreática/metabolismo , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/isolamento & purificação , Piocianina/genética , Piocianina/metabolismo , Fatores de Virulência/genéticaRESUMO
UNLABELLED: Pseudomonas aeruginosa is a Gram-negative bacillus frequently encountered in human diseases. P. aeruginosa produces a large number of secreted and cell associated virulence factors. Their production is coordinated by various systems of gene regulation. The correlation and sequential intervention of regulation systems during a pulmonary infection have not been determined yet. OBJECTIVE: The aim of this study was to analyze the expression of three P. aeruginosa virulence genes (exoS, lasI, and algD) during the first seven days of chronic lung infection. To do so, mice were infected intratracheally with agarose beads containing P. aeruginosa. RESULTS: The results were a progressive decrease of exoS transcription and an increase of algD, and lasI transcription during infection. This dynamic evolution was consistent with the clinical observation, which demonstrated a progressive loss of type III secretion system function and an increase in the mucoid phenotype development in P. aeruginosa strains from cystic fibrosis patients. CONCLUSION: The development of a P. aeruginosa pulmonary chronic infection associates a decrease of gene expression related to a type III secretion system and an increase of alginate production.
Assuntos
Infecções por Pseudomonas/fisiopatologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , Virulência/genética , Animais , Primers do DNA , Modelos Animais de Doenças , Regulação Bacteriana da Expressão Gênica , Camundongos , Pseudomonas aeruginosa/isolamento & purificação , Transcrição GênicaRESUMO
OBJECTIVES: Streptococcus pneumoniae is the leading cause of community-acquired pneumonia. We aimed to analyze the epithelial response to S. pneumoniae-induced lung injury. METHODS: Using an in vitro model with 16HBE cells and experimental in vivo murine model of acute lung injury, we analyzed the epithelial response to S. pneumoniae. Lung epithelial cell monolayers were exposed to S. pneumoniae and permeability was assessed by transepithelial resistance (TER) measurement and organization and expression of junction proteins. Functional consequences were studied with an in vivo murine model measuring alveolar permeability, distal alveolar fluid clearance (DAFC), and the alveolar inflammatory response. RESULTS: In vitro, S. pneumoniae induced a dose-dependent decrease in transepithelial resistance, which was associated with significant modifications in the organization of junction proteins assessed by immunofluorescence staining and expression after 6hours of exposure. In vivo, S. pneumoniae induced a transient increase in alveolar permeability with an adequate increase in DAFC 6hours post infection. In a second phase, a permanent increased permeability was associated with a major decrease in DAFC. CONCLUSION: Overall, the epithelial response to S. pneumoniae followed a biphasic pattern with an initial reversible increase in permeability related to the alteration of tight and adherens junctions and a second phase associated with an epithelial injury with a major increase in permeability with a decreased DAFC reflecting an injured alveolar capillary barrier.